Add runtime version reporting

internal/runtimeinfo/version.go

@@ -0,0 +1,26 @@
+// Package runtimeinfo implements the private runtime version state used by the
+// public buildinfo facade.
+package runtimeinfo
+
+import "runtime/debug"
+
+var injectedVersion string
+
+// Version returns the injected version or the running executable's main module
+// version, falling back to "dev" when neither provides a release identifier.
+func Version() string {
+	return version(injectedVersion, debug.ReadBuildInfo)
+}
+
+func version(injected string, readBuildInfo func() (*debug.BuildInfo, bool)) string {
+	if injected != "" {
+		return injected
+	}
+
+	info, ok := readBuildInfo()
+	if ok && info != nil && info.Main.Version != "" && info.Main.Version != "(devel)" {
+		return info.Main.Version
+	}
+
+	return "dev"
+}

internal/runtimeinfo/version_test.go

@@ -0,0 +1,57 @@
+package runtimeinfo
+
+import (
+	"runtime/debug"
+	"testing"
+)
+
+func TestVersion(t *testing.T) {
+	tests := []struct {
+		name     string
+		injected string
+		info     *debug.BuildInfo
+		ok       bool
+		want     string
+	}{
+		{
+			name:     "injected version takes precedence",
+			injected: "v1.2.3",
+			info:     &debug.BuildInfo{Main: debug.Module{Version: "v4.5.6"}},
+			ok:       true,
+			want:     "v1.2.3",
+		},
+		{
+			name: "main module version",
+			info: &debug.BuildInfo{Main: debug.Module{Version: "v4.5.6"}},
+			ok:   true,
+			want: "v4.5.6",
+		},
+		{
+			name: "missing build information",
+			want: "dev",
+		},
+		{
+			name: "development main module",
+			info: &debug.BuildInfo{Main: debug.Module{Version: "(devel)"}},
+			ok:   true,
+			want: "dev",
+		},
+		{
+			name: "empty main module version",
+			info: &debug.BuildInfo{Main: debug.Module{}},
+			ok:   true,
+			want: "dev",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := version(test.injected, func() (*debug.BuildInfo, bool) {
+				return test.info, test.ok
+			})
+			if got != test.want {
+				t.Fatalf("version() = %q, want %q", got, test.want)
+			}
+		})
+	}
+}

internal/versioncontract/injection.go

@@ -0,0 +1,7 @@
+// Package versioncontract holds the internal contract shared by runtime
+// version reporting and the release builder.
+package versioncontract
+
+// InjectedVersionLinkerSymbol is the -X linker target used to set the runtime
+// version. Keep it in sync with runtimeinfo.injectedVersion.
+const InjectedVersionLinkerSymbol = "gitea.maximumdirect.net/eric/ReleaseKit/internal/runtimeinfo.injectedVersion"